It kind of makes me wonder why we don't see 3D-printers which use paper pulp as the building material .. when I was younger we learned to make our own recycled paper by building the pulp from scraps, and it was an intriguing and inspirational process.

Imagine a 3D printer that you place underneath the shredder tray, add a bit of water too now and then, and come back later to find a nicely printed recyclable widget and/or grommet for much fun.